Renewable-filament lamp



M. V. COLEMAN RENEWABLE FILAMENT LAMP Oct. 30, 1928.

Filed May 15, 1926 2 Sheets-Sheet 1 ATTORNEV WITNESS:

Oct. 30, 1928.

M. v. COLEMAN RENEWABLE FILAMENT LAMP Filed May 15, 1926 2 Sheets-Sheet Mali 57:16 aZema/n INVENTOR I ATTO RNEY WITNESS Patented Oct." 30, 1928.

UNITED." STATES MELVIN VANCE COLEMAN, OF CUMBERLAND, MARYLAND.

RENEWABLE-FILAMENT LAMP. A

Application filed May 15,

This invention relates to electric incandescent lamps, radio tubes and the like, and has for its object the provision of a novel construction for devices of this class whereby disassembling may be easily effected for the purpose of renewing a broken orburned out filament, and 'reassembling just as easily effected without the employment of elaborate and expensive apparatus. j

An importantand more specific ob ect is the provision of a bulb or tube or other lamp devicehaving a filament, so constructed that the parts thereof will be held together by the necessary vacuum and capable of separation by the simple act of releasing the vacuum when repairing is needed. I

, Another object of the invention is to provide a novel valve structure whereby a suction pump may be easily attached for the purdose of exhausting the air after the parts have been disassembled, a new filament placed in position, and the parts reassembled.

An additional object is to providea lamp or tube structure which will be comparatively simple and inexpensivein manufacture, easy to repair, positlve in action, eiiicient and durable in service,and a general improvement in thejart.

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With the above and other objects and advantages in view, the invention consists in the novelconstruction and arrangement of elements to be hereinafter 'more fully described and claimed, and illustrated in the accompanying drawings, in which 2- Figure 1. is a longitudinal section through a radio vacuum tube constructed in accord ance with the invention, this view being'talren on the line 1-1 of Figure 2.

Figure 2 is a plan view. V o T Figure 3 is a section taken 011 the line 33 of Figure 2 butshowing a suction pump applied for exhausting the air subsequent to repairing.

1 Figure 4 is a an incandescent lamp, rectifier, bulb or the like showing it constructed in accordance with the invention. a

Figure 5 is a. detail section through the valve used in connection with either form of tube or bulb.

Figure 6 is a detail jsec tion on 66 of Figure 5, and i I Figure 7 is a view similar to Figure 5 but showing, in enlarged section, the lower end of the suction pump applied thereto.

longitudinal section through i the line 7 1926. Serial No. 109,387.

Referring more particularly to the draw lngs, and especially to Flgures 1 to 3 inclusive, I have'shown aradio vacuum tube includmg a receptacle or casing 10 of suitable mate- The device further includes a cap or cover 16 adapted to fit upon the upper edge of the casing 10 and provided with a depending flange 18 fitting within the casing. To insure a tight joint, use is made of a suitable rubber or other flexible gasket 19 whichfits upon the ledge or shoulder'14 and which engages beneath the outer portion of the cover. Ex-. tending through the cover are terminal members preferably formed as screws 20 which have their heads 21 located beneath the cover and which have suitably secured thereto conductors 22 which extend down into the supporting structure 23 and which are anchored therein. Carried by this supporting structure 23 are the plates, 3

ments necessary in a vacuum tube, these elerid and filament elements being indicated respectively by the numerals 24, 25, and 26. The conductors 22 are connected, within the supporting member 23,, with the respective terminals of these vacuum tube elements and it will therefore be apparent that all the vacuum tube elements are supported from the cover so thatwhen, the cover is'removed from the casing 10, all these elements will be removed along with it.

Clearly, it is easily possible to provide clamp ing nuts 27 on the screws 20 for holding them in place, and it is equally clear that the terminal screws carry binding nuts 28 by means of which connections withlthe different elements in a radio set or the lilre may be made.

The cover 16 also carries a valve device indicated generally by the numeral 29, the valve. device including a cup-like body 30 secured upon the cover for instance by means 01' having a reduced neck 31 passing throughan opening 32 in the cover, the neck being subsequently upset or flattened out as indicated at 33 to provide a retaiuingheud.

The member 30 is formed with a chamber 34 having a relatively small passage 35 comniunicating therewith, a valve seat, preferably of conical shape and indicated by the numeral 36 being provided at the juncture of this passage with the chamber. The upper portion of the chamber is threaded as indicated and normally engaged therein is an externally threaded cap 3? having a knurled or milled head 38 so that it may be readily grasped and turned. Depending from the. center of the underside of the cap member 37 a stem it) carrying a valve ll which coacts with the seat; 36 for sealing the same. The cap 37 is Formed with a threaded reees: l2 with which communicates a V-shaped passage 43 so that when the cap is unscrewed communication between the interior of the casing 1t) and the atnmsphere will be obtained.

In combination with the device, use is made of a. pump it which is shown as including a barrel or cylinder to closed at its ends by ca us 46 and t7, the latter of which is provided with a depending threaded extension 48 adapted to be screwed into the threaded recess 42. this reduced extension having a passage 1 9 therein. Slidably mounted within the pump barrel or cylinder e15 is a piston or plunger 50 of suitable construction carried by a plunger rod 51 which is slidable through the cap 4:6 and which carries an operating handle The cap -16 is provided with an air vent In the operation, it will be apparent: that when the vacuum tube or other device shown in Figures 1 and 2, as well as 3, needs to have its filament replaced, it is merely necessary that the operator or user unscrew the cap 37 so as to disengage the valve it from the seat 36. lVhen this is done, atn'iospheric pressure or air enters the casing 10. as will be readily apparent. The cover 16 should then be detached from the casing 10. all the interior mechanism being removed with the cap. \Vhen this is done. it is of course apparent that the broken or burnt out filament may be readily replaced with a new one, subsequently to which the cap is replaced in position so that the working parts will again be arranged or disposed within the casir 10. While the cap 37 is still unscrewed to such an extent that the valve 4:1 is out of engagement with the seat- Sti, the reduced extension or nipple 48 of the pump is screwed into the threaded recess 12 and the pump plunger or rod, and the piston carried thereby, should then be reciprocated so as to exhaust the air from the interior of the casing; it). It. is of course obvious that the valve device it carried by the stem or extension member it) must he slidable with respect thereto so as to constitute a check valve. Clearly, then. upon each upward movement of the pump plunger or piston 50. a certain amount; oi air will be drawn out of the casing 10. the valve ll innnediately resenting as soon as the movement ol' the piston or plunger ceases. By operating the pump for a sullicient length oi time. it quite apparent that the air within the casing 10 will be rarefied or exhausted to a sutlieient 'the cover H In Figure 4-, l have shown the same prin ciple applied to an incandescent lampdhoue-h of course it is equally well applicable to a rectifier bulb or the like. leterring to this figure in detail, it will be apparent that the reference character 5t designates the bulb which is provided at its open end with a ledge. or shoulder upon which is mounted a resilient gasl-zet 5t; operating to form a seal with the removable cover member 57 which in the present instance, formed with an extension 58 equippedwith a threaded metallic shell :39 so as to be capable of being screwed into an ordinary electric light socket in a well known and custon'iary manner. Dcpending from the cover member 57 a support (30 which carries the filament (31., the terminals of which are brought. out through the extension 58, one being, connected with the shell 59 and the other being connected with the central contact 62 of the bulb. The valve device indicated in general by the numeral 29, and described in full above, is provided on in exactly the same manner as on the first; described form of the invention which d iscloses a vacuum tube for radio purposes or the like. The operation is ot course exactly the same 'for this form of the device as for the first described form and further elaboration should therefore be unnecessary.

It might be mentioned in passing. that the specific construction of the check valve device embodies a'uide arms 41 carried by the valve -11. and slidable with respect: to the stem 40, though ei'igageable with an enlargement it) on the lower end ol' the stem it) so as to limit. the movement.

From the foregoing description and a study of the drawings. it will be apparent that I have thus provided a comparatively simple. and inexpensive construction for radio vacuum tubes. rectifier bulbs. incandescent lamps or any other object or devices cur bodying a tilan'ient, and in which the filament is necessarily operated in a vacuum. ously, by providiusr a construction in which the parts may be disasscml'iled to permit replacement; of a burnt out or broken filament. a great saving will be etl'ected inasmuch as it: is not. necessary to discard the entire tube. bulb or the like whenever a replacement is needed. it. is really believed that the construction, operation and advantages will be Inn readily apparent to one skilled in the art without further explanation.

While I have shown and described the preferred embodiment of the invention, it should be understood that I reserve the right to make such changes in the form, construc tion and arrangement of parts as will not depart from the spirit of the invention or the scope of the subjoined claim.

Having thus described the invention, I claim 1 In a renewable filament vacuum tube, a bulb of glass having one end open and formed with a thickened reinforcing portion provided With a seat, a cover of insulatr ing material telescopically engaged with said seat, gasket means between the cover and the seat, a plurality of terminal elements rigidly secured to'and carried by the cover, a filament, a grid and a plate electrode located ,Within the bulb and supported by conductors MELVIN VANCE COLEMAN. 

